研究表明，身体中部脂肪过多与大脑体积较小有关

研究表明，身体中部脂肪过多与大脑体积较小有关

If you're too heavy, especially around your middle, you probably have shrunken gray matter volume in your brain, according to a study published Wednesday in the journal Neurology. Gray matter contains most of your brain's 100 billion nerve cells, while white matter is filled with nerve fibers that connect the brain regions.

根据周三发表在《神经学》杂志上的一项研究，如果你太胖了，特别是在你的腰部，你的大脑中灰质的体积可能会缩小。灰质包含了大脑1000亿个神经细胞中的大部分，而白质则充满了连接大脑各区域的神经纤维。

"Previous studies have shown associations between gray matter atrophy and risk of developing dementia," study author Mark Hamer, a professor of exercise as medicine at Loughborough University in England, wrote in an email.

“之前的研究已经表明，灰质萎缩与患痴呆症的风险之间存在关联，”研究报告作者、英国拉夫堡大学运动医学教授马克·哈默在电子邮件中写道。

Obesity linked to reduced brain volume in four regions

肥胖与四个区域的脑容量减少有关

The study of 9.652 middle-age people in the UK measured body mass index (BMI) and waist-to-hip ratio. BMI is a formula involving a person's weight and height; a BMI score between 18.5 and 24.9 is considered healthy, while above 30 is considered obese. Similarly, the waist-to-hip ratio is scored, and a high score -- above 0.90 for men and above 0.85 for women -- means a person has central obesity, or a bigger belly than hips.

这项研究调查了9652名英国中年人，测量了他们的身体质量指数(BMI)和腰臀比。BMI是一个包含一个人的体重和身高的公式;BMI指数在18.5到24.9之间被认为是健康的，超过30被认为是肥胖的。同样地，腰臀比也会被计算在内，如果男性的腰臀比高于0.90.女性的腰臀比高于0.85.那么这个人就属于中枢性肥胖，也就是腹部比臀部大。

Based on these criteria, nearly one in five of the study participants was found to be obese. Hamer and his co-researchers also used an MRI to scan participants' brain volume. The researchers factored in age, physical activity, smoking and high blood pressure, all of which might lead to reduced volume.

根据这些标准，近五分之一的研究参与者被发现患有肥胖症。哈默和他的同事们还用核磁共振扫描了参与者的脑容量。研究人员将年龄、体育活动、吸烟和高血压都考虑在内，所有这些因素都可能导致体重下降。

What did they find? People with higher numbers on both BMI and waist-to-hip ratio had the lowest gray matter volume. "The reductions in brain size increase in a linear fashion as fat around the middle grew larger," Hamer wrote.

他们发现了什么?BMI和腰臀比较高的人灰质体积最低。哈默写道:“随着腰部脂肪的增加，大脑体积的缩小呈线性增长。”

"It's unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain," Hamer said.

“目前还不清楚是大脑结构异常导致了肥胖，还是肥胖导致了大脑的这些变化，”哈默说。

Potential causes of lower brain volume

脑容量下降的潜在原因

Cara Bohon, an assistant professor in the Department of Psychiatry and Behavioral Sciences at the Stanford University School of Medicine, wrote in an email that the study's findings are "not particularly new or surprising."

斯坦福大学医学院精神病学和行为科学系的助理教授卡拉·博洪在一封电子邮件中写道，这项研究的发现“并不特别新，也不令人惊讶”。

The study's strength is its size with "a sample of almost 10.000 individuals," wrote Bohon, who was not involved in this research. Previous studies had come to similar conclusions, but few participants were involved, so scientists could not feel confident in the results, she explained.

这项研究的优势在于它的规模，“样本几乎有1万人，”博洪写道，他没有参与这项研究。她解释说，之前的研究也得出了类似的结论，但参与者很少，所以科学家对结果没有信心。

"One particularly interesting finding is that, among individuals with obesity, those with greater waist to hip ratio (a marker of visceral fat around the abdomen), showed even lower gray matter volume," Bohon said. This connection between reduced brain volume and abdominal fat could suggest that inflammation and vascular factors may be at work.

博洪说:“一个特别有趣的发现是，在肥胖人群中，腰臀比(腹部周围内脏脂肪的标志)越高，灰质体积越小。”脑容量减少和腹部脂肪之间的这种联系可能表明炎症和血管因素可能在起作用。

Future research should explore inflammation, nutrition and vascular health to better understand potential links between brain health and obesity, she said. Bohon's own research suggests that weight loss can reverse brain changes, as it showed that when people lost weight, whether a lot or a little, brain volume improved.

她说，未来的研究应该探索炎症、营养和血管健康，以更好地了解大脑健康和肥胖之间的潜在联系。博洪自己的研究表明，减肥可以逆转大脑的变化，因为它表明当人们减重时，无论减重是多还是少，大脑容量都会增加。